5. contains axons that arise in the  oculomotor nucleus (which innervates all of the oculomotor muscles except the superior oblique and lateral rectus)  Edinger–Westphal nucleus (which sends preganglionic parasympathetic axons to the ciliary ganglion).

6.  leaves the brain on the medial side of the cerebral peduncle, behind the posterior cerebral artery and in front of the superior cerebellar artery.  then passes anteriorly, parallel to the internal carotid artery in the lateral wall of the cavernous sinus, leaving the cranial cavity by way of the superior orbital fissure.

7.  The somatic efferent portion of the nerve innervates the levator palpebrae superioris muscle; the superior, medial, and inferior rectus muscles; and the inferior oblique muscle

8.  The visceral efferent portion innervates two smooth intraocular muscles: the ciliary and the constrictor pupillae.

9.  Strabismus (squint) is the deviation of one or both eyes.  In internal strabismus, the visual axes cross each other  in external strabismus, the visual axes diverge from each other

10.  Diplopia (double vision) is a subjective phenomenon reported to be present when the patient is, usually, looking with both eyes  caused by misalignment of the visual axes

11.  Ptosis (lid drop) is caused by weakness or paralysis of the levator palpebrae superioris muscle  seen with lesions of nerve III and sometimes in patients with myasthenia gravis.

12.  External ophthalmoplegia is characterized by divergent strabismus, diplopia, and ptosis.  The eye deviates downward and outward.  This corresponds to the weaknesses of the medial, superior, and inferior recti and the inferior oblique muscles.  position of the eye is described by the mnemonic "down and out."

13.  Internal ophthalmoplegia is characterized by a dilated pupil and loss of light and accommodation reflexes.  There may be paralysis of individual muscles of nerve III

15.  Isolated involvement of nerve III (often with a dilated pupil) occurs as an early sign in uncal herniation because of expanding hemispheric mass lesions that compress the nerve against the tentorium

16.  Nerve III crosses the internal carotid, where it joins the posterior communicating artery; aneurysms of the posterior communicating artery thus can compress the nerve  Isolated nerve III palsy also occurs in diabetes, presumably because of ischemic damage, and when caused by diabetes, often spares the pupil

17.  the only crossed cranial nerve  originates from the trochlear nucleus, which is a group of specialized motor neurons located just caudal to the CN III nucleus within the lower midbrain.

18.  Axons cross within the midbrain, and then emerge contralaterally on the dorsal surface of the brain stem.  nerve then curves ventrally between the posterior cerebral and superior cerebellar arteries (lateral to CN III).

19.  continues anteriorly in the lateral wall of the cavernous sinus and enters the orbit via the superior orbital fissure.  innervates the superior oblique muscle

20.  rare condition  slight convergent strabismus and diplopia on looking downward  patient cannot look downward and inward - has difficulty in descending stairs.  head is tilted as a compensatory adjustment; this may be the first indication of a trochlear lesion.

21.  arises from neurons of the abducens nucleus located within the dorsomedial tegmentum within the caudal pons.  emerges from the pontomedullary fissure, passes through the cavernous sinus close to the internal carotid, and exits from the cranial cavity via the superior orbital fissure

23.  long intracranial course makes it vulnerable to pathologic processes in the posterior and middle cranial fossae.  innervates the lateral rectus muscle

24.  few proprioceptive fibers from the muscles of the eye are present in nerves III, IV, and VI and in some other nerves that innervate striated muscles.  central termination of these fibers is in the mesencephalic nucleus of V

25. most common owing to the long course of nerve VI. weakness of eye abduction convergent strabismus and diplopia. affected eye deviates medially, i.e., in the direction of the opposing muscle